Trends and Topics in Eye Disease Research in Pubmed from 2010 to 2014
Total Page：16
File Type：pdf, Size：1020Kb
Trends and topics in eye disease research in PubMed from 2010 to 2014 Christophe Boudry1,2,3, Eric Denion4, Bruno Mortemousque5,6 and Fre´deric Mouriaux5,6 1 Me´dia normandie, Normandie Universite´, Universite´ de Caen Normandie, Caen, France 2 URFIST/Ecole Nationale des Chartes, Paris, France 3 Laboratoire “Dispositifs d’Information et de Communication a` l’E` re Nume´rique,” Conservatoire National des Arts et Me´tiers, Paris, France 4 Service d’Ophtalmologie, CHU Coˆte de Nacre, Caen, France 5 Service d’Ophtalmologie, CHU Rennes, Universite´ Rennes 1, Rennes, France 6 Faculte´ de Me´decine, Rennes, France ABSTRACT Background: The purpose of this study is to provide a report on scientific production during the period 2010–2014 in order to identify the major topics as well as the predominant actors (journals, countries, continents) involved in the field of eye disease. Methods: A PubMed search was carried out to extract articles related to eye diseases during the period 2010–2014. Data were downloaded and processed through developed PHP scripts for further analysis. Results: A total of 62,123 articles were retrieved. A total of 3,368 different journals were found, and 19 journals were identified as “core journals” according to Braford’s law. English was by far the predominant language. A total of 853,182 MeSH terms were found, representing an average of 13.73 (SD = 4.98) MeSH terms per article. Among these 853,182 MeSH terms, 14,689 different MeSH terms were identified. Vision Disorders, Glaucoma, Diabetic Retinopathy, Macular Degeneration, and Cataract were the most frequent five MeSH terms related to eye diseases. The analysis of the total number of publications showed that Europe and Asia were the most productive continents, and the USA and China the most productive countries. Interestingly, using the mean Five-Year Impact Factor, the two most productive continents were North America Submitted 9 September 2015 Accepted 11 December 2015 and Oceania. After adjustment for population, the overall ranking positions changed Published 7 January 2016 in favor of smaller countries (i.e. Iceland, Switzerland, Denmark, and New Zealand), Corresponding author while after adjustment for Gross Domestic Product (GDP), the overall ranking Christophe Boudry, positions changed in favor of some developing countries (Malawi, Guatemala, [email protected] Singapore). Conclusions: Due to the large number of articles included and the Academic editor numerous parameters analyzed, this study provides a wide view of scientific Tifei Yuan productivity related to eye diseases during the period 2010–2014 and allows us to Additional Information and better understand this field. Declarations can be found on page 13 DOI 10.7717/peerj.1557 Subjects Ophthalmology, Science and medical education Copyright Keywords Eye diseases, Ophthalmology, Science publishing, Journals, Socioeconomics, 2016 Boudry et al. Bibliometrics Distributed under Creative Commons CC-BY 4.0 How to cite this article Boudry et al. (2016), Trends and topics in eye disease research in PubMed from 2010 to 2014. PeerJ 4:e1557; DOI 10.7717/peerj.1557 INTRODUCTION Bibliometrics has been defined as the use of statistical methods to analyze a body of literature to reveal historical development through the scientific and quantitative study of publications (Young & Belanger, 1983). Applications of bibliometrics are numerous: determining a library purchasing policy (Garfield, 1972), studying the structure of the network of a scientific field (Wallace, Larivie`re & Gingras, 2012), and mapping the literature related to a research field such as health literacy (Kondilis et al., 2008) or cancer research (Glynn et al., 2010). Bibliometrics can also evaluate the speed of publication of manuscripts in journals (Chen, Chen & Jhanji, 2013), allow one to recognize new topics in the literature (Boudry, 2015), or even evaluate research and researchers (Hirsch, 2005). Viewed as an objective and quantifiable assessment of research output, such bibliometrics are inextricably linked with research funding, and an investigator must possess a strong publishing background to obtain the financial grants necessary for further work (Geisler, 2000). Few bibliometric studies have appeared in the literature in the field of ophthalmology. Although some analyses have been done on specific countries, (Kumaragurupari, Sieving & Lalitha, 2010; Katibeh, Moein & Javadi, 2011; Schlenker, Manalo & Wong, 2013) continents or territories (Ugolini et al., 2001; Sweileh et al., 2015), sub-specialties (Zhao et al., 2011; Gupta, Bala & Gupta, 2014; Boudry & Mouriaux, 2015), or production of a selection of ophthalmologic journals (Kumbar & Akhtary, 1998; Guerin et al., 2009; Kumar, Cheeseman & Durnian, 2011; Liesegang, 2011), no attempts have been made to describe the field “eye diseases.” The main purpose of this paper is to provide a report on scientific production in the field of eye diseases. For this, core journals have been identified, and frequency and distribution of MeSH terms in articles calculated. Furthermore, the geographical distribution and the temporal trend of papers published between 2010 and 2014 have been investigated with ad hoc geographical analyses evaluating literature production and weighted according to major socioeconomic variables, i.e. population size and Gross Domestic Product (GDP). MATERIAL AND METHODS Data were downloaded from PubMed in Extensible Markup Language (XML) and were processed through developed Hypertext Preprocessor language (PHP) scripts, then were imported to Microsoft Excel 2010 (Microsoft, Redmond, USA) for data processing. Bibliographic search The search for papers to be included in this study was carried out on January 16th 2015, using the PubMed database (http://www.ncbi.nlm.nih.gov/pubmed), developed by the National Center for Biotechnology Information (NCBI) at the National Library of Medicine (NLM). PubMed was chosen because it is the most widely used in medicine (Falagas et al., 2008). The search strategy was the following: eye diseases [MH] AND journal article [PT] AND 2010:2014 [DP] where MH stands for “Medical Subject Headings,” DP “Date of Publication,” and PT “Publication Type.” “Journal Article” includes the following publication types: journal articles, introductory journal articles, and reviews. MeSH is the National Library of Medicine’s controlled vocabulary thesaurus Boudry et al. (2016), PeerJ, DOI 10.7717/peerj.1557 2/16 (http://www.nlm.nih.gov/pubs/factsheets/mesh.html) and consists of sets of terms named “MeSH terms” arranged in a hierarchical structure (called a MeSH tree) with more specific terms arranged beneath less specific terms. In the indexing process, 2 to 50 MeSH terms are assigned to PubMed documents by a team of trained experts (indexers) to properly identify the content, and indexers always index as specifically as possible (MEDLINE Indexing Online Training Course, 2015). It is worth mentioning that it is not obligatory for author’s keywords to be taken into account by indexers to determine MeSH terms of an article (Boudry, 2015, personal data). The MeSH term “Eye Diseases,” the definition of which in the NLM-controlled vocabulary thesaurus is “Diseases affecting the eye,” was chosen because it covers all diseases of the eye when used in a PubMed search. Indeed, when using a MeSH term in a PubMed search, articles that carry the specified MeSH term are retrieved, but so are all of the articles that carry any of the more specific MeSH terms located beneath it in the tree structure. Thus, searching with the MeSH term “Eye Diseases” automatically includes all the MeSH terms located beneath “Eye Diseases” corresponding to diseases of the eye in general. Analysis of MeSH terms As done in other studies (Ugolini et al., 2007, 2010; Ramos, Gonza´lez-Alcaide & Bolan˜os- Pizarro, 2013; Neri et al., 2015), an analysis of the MeSH terms used by PubMed indexers to classify the articles was done by calculating their frequency in the retrieved articles. Check tags, i.e. MeSH terms obligatorily used by indexers to describe recurrent patterns in medical articles, were excluded from this frequency analysis because of their compulsory and recurrent character. They are shown in Supplemental Table S1. The co-occurrence is the simultaneous association of two identical MeSH terms in different articles. The frequency and the percentage of co-occurrence of the MeSH terms located beneath the MeSH term “Eye Diseases” in articles has been calculated. Likewise, the frequency of all other MeSH terms not situated beneath the MeSH term “Eye Diseases” retrieved has also been calculated. Analysis of growth of literature The average yearly growth rate of the literature related to eye diseases was calculated as the mean percentage of annual growth rate for the period studied using the equation: Annual Growth Rate = Current Year Total Number of Articles – Previous Year Total Number of Articles/Previous Year Total Number of Articles (Deshazo, Lavallie & Wolf, 2009). The average yearly growth rate was also calculated for the whole PubMed database for the period 2010–2014. Bradford’s law Bradford’s law has been used extensively in the information science literature to describe the dispersion of articles in any scientific field (Goffman & Warren, 1969), or to identify “core journals” of serial titles (Deshazo, Lavallie & Wolf, 2009; Venable et al., 2014). Bradford’s law states that “If scientific journals are arranged in order of decreasing productivity of articles on a given subject, they may be divided into a nucleus of Boudry et al. (2016), PeerJ, DOI 10.7717/peerj.1557 3/16 periodicals more particularly devoted to the subject and several groups or zones containing the same number of articles as the nucleus.” To identify the core journals containing articles dedicated to eye diseases, Bradford’s law was applied by dividing the journals ranked according to publication output frequency into three groups with each group representing approximately the same number of articles. Analysis of journals and language of publication The 2013 Journal Citation Reports (JCR) (Thomson Reuters, New York, USA) was used for Impact Factor (IF) determination and for the ranking of the journal in the category “Ophthalmology” of the JCR.